Posts
1338
Joined
10/29/2007
Location
Yorba Linda, CA, USA
Edited Date/Time
12/12/2021 7:30pm
Checking over photos of the 22' HRC machines and noticed some different engine hangers...Any idea what the benefit would be going from stock aluminum to steel hangers? I know the WCL and FCP units are engineered for a different 'feel', but they're still aluminum pieces. I don't recall any rider in recent memory going to steel from an OE aluminum spec. Maybe Villopoto back in 09'-11' Kawi years? Photos in the link below from SwapMoto:
https://www.swapmotolive.com/team-honda-hrc-race-bikes/photo-gallery/
https://www.swapmotolive.com/team-honda-hrc-race-bikes/photo-gallery/
Sorry couldn’t resist.
Steel will be more flexible laterally for the same strength and weight as aluminium or titanium because it will be thin.
Also simple and inexpensive to make in house.
The Shop
Luxon 4-Post Bar Mounts
$189.95 - $239.95
DeCal Works Huge Plastic Inventory of UFO and Polisport kits.
Free shipping: VITALMX
Bu
Their purpose may be to fit a guide for chain control.
Until we see multi post rig testing of different mounts on MX bikes with force/deflection objective measurement
correlated with on track performance improvement it will be all rider subjective.
Rider feel with the marketing BS over the top and positive affirmation bias by the consumer powers it now.
Keeping is simple, let's just look at bending stiffness of a plate due to material stiffness and thickness. And let's use steel as a baseline in comparisons.
Titanium is roughly 1/2 the stiffness of steel (and also about 1/2 the weight). Aluminum is about 1/3 the stiffness of steel (and also about 1/3 the weight).
So for the same weight of all three, you could have a steel plate, a titanium plate that's twice the thickness, and an aluminum plate that's three times the thickness. They would all be about the same stiffness in tension/compression too.
But in bending, the stiffness would be VERY different. That's because the thickness comes into play in bending (the moment of inertia is related to the cube of the thickness). The titanium plate would be about 6 times stiffer than the steel plate and the aluminum plate would be about 9 times stiffer than the steel plate!
So you can make a part that's subject to bending much stiffer and stronger by increasing its thickness than you can by changing the material. If your part is subject to bending and tension/compression (and torsion), like most parts, you can achieve the desired stiffness properties by altering the thickness, material layout, and material itself.
Regarding engine mounts, it's unlikely anyone is actually doing that as I've yet to see any evidence of it. They're just designing (not engineering) a part that looks cool, making it, and trying it. Do that enough times and they'll eventually stumble on a design that's better than stock, which is arguable to many.
As for fasteners, it doesn't matter if the bolt is steel or titanium. As long as it's torqued correctly (tensioned, really), no one will be able to tell the difference. That won't apply so much to large parts like axles, but it certainly does for things like engine mount bolts, axle pinch bolts, triple clamp bolts, etc. Riders change those because they think they can feel the difference, and sometimes that's more important than actually telling the difference as the mental side of moto is huge. But any engineers seeing that will just laugh!
These are all rough comparisons because this is for simple tension/compression and bending of a flat plate. It's good for a general idea, but it gets more complicated with anything of a more complex shape.
Full tank or empty tank I don’t feel the difference. And that’s more weight than $2000 in titanium can remove.
Pit Row
It dawned on me the other day, that ktm hangers bolt into the cylinder vs the head. Interesting that ktm save weight everywhere, such as two bolts either side of the frame mounts vs a heavier single long bolt clamping both sides at once.
Go look at an X or L frame.
If anyone wants some really flexible mounts I can whip up some 3D printed plastic ones no problem. . .
(Disclaimer: That was 100% a joke, do not put plastic 3D printed engine hangers on your motocross bike)
The Austrian 4-strokes bolt to the head.
As far as breaking the frame.... I had the head stays vibrate loose on my YZ125 a few years ago. Bolt through the head completely went missing. I probably rode a few motos before I noticed it. I felt nothing and I was hitting some pretty big jumps all day. The way I noticed was I heard a slight vibration that sounded like a pipe spring came loose. It was the hanger bracket vibrating against the head. Put a new bolt in and that bike is still going strong about 6 years later.
In the past, ive processed many parts where we need to eliminate steel grain variability from the equation. We typically do this in the CNC nesting software so that parts can only be nested such that they are always going the same grain direction, which could be against or with the grain, but never randomly. With the grain being in the direction of steel mill rolling, against the grain perpendicular to the rolling direction.
The biggest benefit to doing this is that we gain accuracy in the bending/ forming operation. When the incoming flat parts are all homogeneous in grain direction from the sheet steel, the forming accuracy and repeatability becomes much more controllable and bend angle tolerances can be tightened up.
The downside of locking in the grain pattern at the laser or punch cut operation is that the parts typically cannot be nested together as well which usually equals less parts per sheet.
Back just a few years ago, there were some KX450's getting blown head gaskets from the pull up of the head stays.
Nice!
Post a reply to: Steel vs. Aluminum Engine Hangers on 2022 HRC Machines: Luxon, 3DP, ML512 Insight?